From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BA870C433FE for ; Wed, 9 Mar 2022 01:09:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229976AbiCIBKD (ORCPT ); Tue, 8 Mar 2022 20:10:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57498 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230140AbiCIBJO (ORCPT ); Tue, 8 Mar 2022 20:09:14 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 9FC97C7E54 for ; Tue, 8 Mar 2022 16:50:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1646787057; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=sfZ5PwvLnI4LLU34fgHb1e9AhJAkBykiEyb2Klxh090=; b=DSPxgnwtOTO14S3vCCucAmhRnhnNzjro6Fu3zG3H3Uvhm1z2FHXtecKXxwzBagZlODJxOG JZWOeMbVFQDum4o/jIFsjprf5/4U1oqN+P3yAcySkEsUit1taGSbOFCJmNHYdbcITZzRd5 0DHbPtdaiNVbErJuQGuKRUfUQIi44+Y= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-175-dNiZfsEjOdapE2gi6wjFvg-1; Tue, 08 Mar 2022 19:50:54 -0500 X-MC-Unique: dNiZfsEjOdapE2gi6wjFvg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5C41B1006AA6; Wed, 9 Mar 2022 00:50:53 +0000 (UTC) Received: from [10.22.11.135] (unknown [10.22.11.135]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7B38D72427; Wed, 9 Mar 2022 00:50:52 +0000 (UTC) Message-ID: <34bc9788-0459-9126-8aa9-e0d10e9f5b5f@redhat.com> Date: Tue, 8 Mar 2022 19:50:51 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH] mm/list_lru: Optimize memcg_drain_list_lru_node() Content-Language: en-US To: Roman Gushchin Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Muchun Song References: <20220308033009.1400464-1-longman@redhat.com> <3faa2be7-3a08-ee6d-35e8-c4a35e825c77@redhat.com> From: Waiman Long In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/8/22 19:17, Roman Gushchin wrote: > On Tue, Mar 08, 2022 at 10:41:38AM -0500, Waiman Long wrote: >> On 3/7/22 23:39, Roman Gushchin wrote: >>> On Mon, Mar 07, 2022 at 10:30:09PM -0500, Waiman Long wrote: >>>> Since commit 2c80cd57c743 ("mm/list_lru.c: fix list_lru_count_node() >>>> to be race free"), we are tracking the total number of lru >>>> entries in a list_lru_node in its nr_items field. In the case of >>>> memcg_drain_list_lru_node(), there is nothing to be done if nr_items >>>> is 0. We don't even need to take the nlru->lock as no new lru entry >>>> could be added by a racing list_lru_add() to the draining src_idx memcg >>>> at this point. >>>> >>>> Signed-off-by: Waiman Long >>> Hi Waiman! >>> >>> The patch makes total sense to me, however it needs to be rebased at least >>> on top of "mm: list_lru: rename memcg_drain_all_list_lrus to memcg_reparent_list_lrus". >>> >>> Thanks! >>> >>> >> This patch was based on the current linux-next tree which includes commit >> ff221bc26bdd ("mm: list_lru: rename memcg_drain_all_list_lrus to >> memcg_reparent_list_lrus"). I do remember to double-check linux-next before >> sending this patch out. In fact, the same patch can be applied to both linux >> and linux-next tree without problem. > I'm looking at the mm tree (https://github.com/hnaz/linux-mm.git) and clearly > see that commit "mm: list_lru: rename memcg_drain_all_list_lrus to > memcg_reparent_list_lrus" eliminated the function with the name > memcg_drain_list_lru_node(), which your patch is touching. > Currently the function is located in list_lru.c and is named > memcg_reparent_list_lru_node(). > > linux-next is sometimes a bit behind the mm tree. Oh, you are right. I will rebase the patch based on linux-mm. Thanks for the suggestion. Cheers, Longman